Castle Thor, Protected castle in Astenet, Belgium

Castle Thor is a three-winged stone complex around a cobblestone courtyard in Astenet, Lontzen. Its northeast entrance is a single-storey gatehouse of sandstone and bluestone rubble with corner quoins, a slate hipped roof, and a round archway framed by a baroque volute gable with a Madonna and Child in a shell niche. Behind rise the whitewashed two-storey manor house of 1700 and a three-storey square tower with a crenellated top added in the 19th century.

The castle stands on the site of the brewery of the Astenet estate, a fief dependent on the Chapter of Our Lady in Aachen. In 1416 the line passed to the Van der Heyden family, and in 1543 Claire van der Heyden brought it to Jean Molener. Jean Heyendal bought it and had the present house built in 1700; the garden wing followed in 1738. The last Heyendal died in 1806.

The castle preserves original stucco ceilings, leather wallpaper with biblical themes, and oak doors carved in the Louis XIV style within the former chapel area. These decorations reveal how wealthy families adorned their private spaces and what religious imagery held meaning for them.

The property operates as a hotel-restaurant since 1947 and serves accommodation and event facilities. Visitors should note that access may be limited by operating hours and private events hosted at the venue.

The keystone over the round-arched gateway bears the year 1733 and the coat of arms of the Heyendal family, while the courtyard-side keystone reads 1732 with the inscription "sit nomine Domini bene dictum". A weathervane on the gatehouse ridge carries the letters D and L for Doktor Lambertz, owners since 1840.